Just to be a bit pedantic, the FCOM asks you to Monitor the fuel for Imbalance with the caeveat "IF NO FUEL LEAK" , while the ECAM only offers you IMBALANCE------MONITOR. The only point here, is that your TRI will almost certainly want you to prove that you are aware of the potential for a serious fuel leak by checking the fuel page on the SD. I don't think you will get a serious de-brief for only following ECAM, but it shows that you are not just following it parrot fashion.